Technical validity and usability of a novel smartphone connected spirometry device for pediatric patients with asthma and cystic fibrosis.

BACKGROUND Diagnosis and follow-up of respiratory diseases traditionally rely on pulmonary function tests (PFT), which are currently performed in hospitals and require trained personnel. Smartphone connected spirometers, like the Air Next spirometer, have been developed to aid in the home-monitoring of patients with pulmonary disease. The aim of this study was to investigate the technical validity and usability of the Air Next spirometer in pediatric patients. METHODS Device variability was tested with a calibrated syringe. 90 subjects aged 6-16 were included in a prospective cohort study. 58 subjects performed conventional spirometry and subsequent Air Next spirometry. The bias and the limits of agreement between the measurements were calculated. Furthermore, subjects used the device for 28 days at home and completed a subject satisfaction questionnaire at the end of the study period. RESULTS Inter-device variability was 2.8% and intra-device variability was 0.9%. The average difference between the Air Next and conventional spirometry was 40 mL for FEV1 and 3 mL for FVC. The limits of agreement were -270 mL and +352 mL for FEV1 and -403 mL and +397 mL for FVC. 45% of FEV1 measurements and 41% of FVC measurements at home were acceptable and reproducible according to ATS/ERS criteria. Parents scored difficulty, usefulness and reliability 1.9, 3.5 and 3.8 out of 5, respectively. CONCLUSION The Air Next device shows validity for the measurement of FEV1 and FVC in a pediatric patient population. This article is protected by copyright. All rights reserved.